Niacin, also known as vitamin B.sub.3, is the common name for nicotinic acid. The physiologically active form of niacin is niacinamide, also a member of the vitamin B.sub.3 family of compounds. Niacin and niacinamide (nicotinic acid amide) function in the body as components of two coenzymes: nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). Until recently, these vitamin B.sub.3 compounds were used exclusively to treat niacin deficiency and pellegra.
Today, however, vitamin B.sub.3 compounds have also found use in the area of skin care actives. British Patent 1,370,236 describes compositions for skin lightening containing 0.5% to 10% niacin. Similarly, U.S. Pat. No. 4,096,240 discloses the use of 0.1% to 10% niacinamide for skin lightening. Vitamin B.sub.3 compounds have also been found useful in regulating the texture of human skin. See PCT application WO 97/39733, to Oblong et al.
However, when applied to the skin in crystalline form (i.e., powder), vitamin B.sub.3 compounds tend to impart a rough feel to the skin. In the past, the crystalline vitamin B.sub.3 compounds were solubilized in a polar solvent before application to the skin, destroying the crystalline structure and thereby alleviating the rough feel of the crystals. However, solubilization reduced the efficacy of the vitamin B3 compound upon contact with the skin. Thus there exists a need for cosmetic compositions comprising unsolubilized crystalline vitamin B.sub.3 compound(s) which provide improved consumer perceived skin feel. The present inventors have discovered that cosmetic formulations incorporating the crystalline vitamin B.sub.3 compounds of a specific crystalline structure and an emollient improve the consumer perceived feel of the vitamin B.sub.3 compound on the skin. The present inventors have further discovered that these compositions are especially useful to impart vitamin B3 benefits to the lips with improved skin feel when used in lipstick compositions including a solidifying agent.
It is, therefore, an aspect of the present invention to provide cosmetic compositions, preferably anhydrous cosmetic compositions, comprising select crystalline structured vitamin B.sub.3 compounds which improve the appearance and feel of the skin while alleviating the rough feel of the crystalline vitamin B3 compound.
Another aspect of the present invention is to provide anhydrous cosmetic compositions comprising selected crystalline structure vitamin B.sub.3 compounds which improve the feel of the vitamin B.sub.3 compound on the skin.
These and other aspects will become readily apparent from the detailed description which follows.